What is Planck's constant? | Birth of Quantum Mechanics | Transforming physics скачать в хорошем качестве

What is Planck's constant? | Birth of Quantum Mechanics | Transforming physics

To understand Planck’s constant, we need to understand light. Light behaves with something called wave-particle duality. Sometimes it exhibits wave characteristics and sometimes it exhibits particle characteristics. Unfortunately, calling it one or the other would be an incomplete description, as it is really both at the same time. Before Max Planck performed his famous experiment with a black-body radiator in the late 1800s, every respected scientist thought light was a wave. If you have studied waves, you will know that waves exhibit certain behaviors, including reflection, refraction, diffraction, and interference. Scientists had shown that light exhibited all these characteristics and therefore classified it as a wave. Thus, scientists assumed, a light wave could be defined easily by its frequency. However, the wave model of light was unable to explain Planck’s black-body radiation experiment. When he graphed the spectral radiance (intensity of light emitted) versus the wavelength of the light emitted, he obtained a bell curve, which is more closely associated with light being a particle. Completely befuddled, he resorted to curve-fitting. He assumed light was divided up into tiny, little particles called photons. He created an equation to describe the energy of these tiny little particles: E = hf, where E = energy of the photon, f = frequency of the light wave observed, and h = Planck’s constant (a number that varies based on the units). This is the core of what Planck’s constant is. It is simply the ratio between the energy of a single photon in the observed light and the frequency of the light wave as a whole. This is what Wikipedia and all those other sources mean by saying that Planck’s constant is essential to the “quantization” of light - it just means that Planck’s constant helps describe these little particles, or photons of light. NOTE: The description above may suggest that light waves are made up of photon particles. This is not exactly true. Photons behave as particles, but they also behave as waves and therefore you observe light as a wave. For more information, you can read about wave-particle duality online. #plancksconstant